Diameter of a bolt hole is usually taken as

Answer: Option B

Bolt Hole Diameter: In the design of steel structures, the diameter of a bolt hole is an important parameter to ensure proper fitting and to allow for slight misalignments during construction.

Standard Practice: According to standard practice and codes, the diameter of a bolt hole is usually taken as the nominal diameter of the bolt plus an additional allowance to account for tolerances and ease of installation.

Nominal Diameter +1.5 mm: The most common allowance added to the nominal diameter is 1.5 mm. This ensures that the bolt can fit through the hole without being too tight, while also maintaining structural integrity.

Other Options:

Gross diameter of bolt is not a standard term used for determining bolt hole diameter.

Nominal diameter +2.0 mm is not as commonly used as the 1.5 mm allowance.

Nominal diameter of bolt without any additional allowance does not account for tolerances and is not practical for construction.

Therefore, the diameter of a bolt hole is usually taken as Nominal diameter +1.5 mm.